There are more than 2000 species of firefly found in
temperate and tropical environments around
the world. Many species can be found in marshes or in wet, wooded
areas where their larvae
have abundant sources of food.

Biology

Fireflies tend to be brown and soft-bodied, often
with the elytra more
leathery than in other beetles. Though the females of some species
are similar in appearance to males, larviform
females are found in many other firefly species. These females
can often be distinguished from the larvae only because they have
compound
eyes. The most commonly known fireflies are nocturnal, though
there are numerous species that are diurnal.
Most diurnal species are non-luminescent, though some species that
remain in shadowy areas can produce light.

A few days after mating, a female lays her
fertilized eggs on or just below the surface of the ground. The
eggs hatch 3-4 weeks later and the larva feed until the end of the
summer. The larvae are commonly called glowworms, not to be confused
with the distinct beetle family Phengodidae or
fly genus Arachnocampa.
Lampyrid larvae have simple eyes. The term glowworm is also used
for both adults and larvae of species such as Lampyris
noctiluca, the common European glowworm, in which only the
non-flying adult females glow brightly and the flying males glow
only very weakly and intermittently. Fireflies overwinter
(some species for several years) during the larval stage. Some do
this by burrowing underground, while others find places on or under
the bark of trees. They emerge in the spring. After several weeks
of feeding, they pupate for
1 to 2.5 weeks and emerge as adults. The larvae of most species are
specialized predators and feed on other larvae, terrestrial
snails, and slugs. Some are so specialized that
they have grooved mandibles
which deliver digestive fluids directly to their prey. The diet of
adults is variable. It has been reported that some are predatory,
while others feed on plant pollen or nectar.

Light production

Light production in fireflies is due to a
chemical reaction that occurs in specialized light-emitting
organs,
usually on the lower abdomen. The enzyme luciferase acts on luciferin in this organ to
stimulate light emission. Genes coding for these
substances have been inserted into many different organisms (see
Luciferase
- Applications). Luciferase is also used in forensics, and the enzyme has
medical uses. For adult beetles, it is primarily used to locate
other individuals of the same species for reproduction. Many
species, especially in the genus Photinus,
are distinguished by the unique courtship flash patterns emitted by
flying males in search of females. Photinus females generally do
not fly, but give a flash response to males of their own
species.

Bioluminescence is a very efficient process. Some
90% of the energy a firefly uses to create light is actually
converted into visible light. By comparison, an incandescent
electric bulb can convert only 10 percent of total energy used into
visible light, and the remainder is emitted as heat.

Female Photuris
fireflies are known for mimicking the mating flashes of other
fireflies for the sole purpose of predation. Target males are
attracted to what appears to be a suitable mate, and are then
eaten. For this reason the Photuris female is sometimes referred to
as "femme
fatale".

Many fireflies do not produce light. Usually
these species are diurnal, or day-flying, such as those in the
genus Ellychnia. A few
diurnal fireflies that primarily inhabit shadowy places, such as
beneath tall plants or trees, are luminescent. One such genus is
Lucidota.

All fireflies glow as larvae. Bioluminescence
serves a different function in lampyrid larvae than it does in
adults. It appears to be a warning signal to predators, since many firefly
larvae contain chemicals that are distasteful or toxic.

Systematics

Firefly systematics, as with many insects, are
in a constant state of flux, as new species continue to be
discovered. The five subfamilies listed above are
the most commonly accepted ones, though others such as the Amydetinae and
Psilocladinae
have been proposed. This was mainly done in an attempt to revise
the Lampyrinae,
which by and by had become something of a "wastebin
taxon" to hold incertae
sedis species and genera of fireflies. Other changes are
occasionally proposed, such as merging the Ototetrinae
into the Luciolinae, but
the arrangement used here appears to be the most frequently-seen
and stable layout, at least for the time being.

Fireflies and humans

Fireflies were a part of ancient
Mayan
mythology, often being associated with the stars. Further, they
were associated with cigar
smoking and may have had at least one representative in the
pantheon
of Mayan gods
(Lopes 2004).